Getting married for reproduction convenience?

Honestly, I think you're just setting yourself up for disappointment. This has obviously been an issue for a long time between the two of you. What makes you think it won't be any more of a problem several years from now? Seems like it would be an ongoing issue between you two. And there's also the chance of him resenting you in the end. He's more than willing to suppress his attraction to males, right now. But if he finds himself years from now, wanting to act on those suppressed feelings, he will eventually snap. I don't know you or him personally, so all of what I'm saying just might be wrong. I sincerely hope you and him figure things out. Best of luck.